Computer simulations of biotic chiral selection scenarios

Abstract

The biotic scenario of the selection of biological homochirality is one of the most interesting applications of computer modelling to astrobiology. These scenarios have been studied for more than 70 years, yet there are plenty of studies to better assess them, in particular in the development of models of the selective extinction process. In this paper, we review former studies performed by biology-grounded models of this process and present a new class of computer programs: they further demonstrate the complexity of the selective extinction dynamics and the role played into it by non-trivial chemical-physical concepts. Indeed, the results display large and persistent differences between the populations of the two different chiral types, made possible by the freedom of individual populations to fluctuate wildly while the total population is stabilized by the limited availability of chemical energy. Such strong differences ultimately lead to the selective extinction of one of the two types. This way, computer simulations provide increasing evidence in favour of the biotic scenario.

Special issue: Open questions and next steps in astrobiology in Europe – celebrating 20 years of EANA

“…Micca Longo and Longo (2022), (this issue) applying a simulated entry model to Mars by using White Soft Minerals (WSMs) in the form of micro-grains (mimic micrometeorites), show that moderate temperature will be reached and maintained entering the Martian atmosphere with lower entry speed. The WSMs chemical/thermal decomposition process seems much slower than predicted, and this suggests both a possible transfer of organic molecules, and Mars have been a promising collector of matter in this form.…”

“…The results and conclusions presented in this study are not only relevant for the understanding of potential life in the Martian subsurface, but also in other highly radiated environments like on the icy moons of the outer Solar System. Longo et al (2022), (this issue) analyse the biotic scenario of the selection of biological homochirality and revise the biology-grounded models of the selective extinction process highlighting the complexity of the selective extinction dynamics and the nontrivial chemical-physical concepts involved, finally presenting a new class of computer programs. Results show persistent differences between the populations of the two different chiral types and suggest a selective extinction of one of the two types based on the freedom of individual populations to fluctuate wildly while the total population is stabilized by the limited availability of chemical energy.…”